hi, i am pleased you are going to get it out. take things easy when you get home after removal and don't bend or lift anything for a few days to let the uterus and surrounding muscles settle down a bit.
the reason that you felt so much better while you were pregnant is probably because you had good levels of natural progesterone and therefore you were not estrogen dominant at that time. you need both hormones for a healthy pregnancy but progesterone is what keeps you pregnant - misscarriages are often caused through lack of progesterone and/or too much estrogen. Progesterone naturally reduces in level towards the end of pregnancy as the estrogen takes over and stimulates the birth itself. From what i have read so far, it appears that Synthetic progesterone as in mirena and other birth control products does not act in the same way as the natural version and yet still takes up the progesterone receptors in the body, thus preventing any available natural progesterone from doing its thing and allowing us to gradually build up estrogen (because we tend to have more estrogen anyway, due to Western lifestyle etc). So it sounds like looking into estrogen dominance is a way to go for you, to really understand what is goin on in your body and hopefully to be able to work on solving the problems. I bet that if you can get your estrogen levels lower in ratio to the progesterone, your joint pains will be less and you should have no more PMS etc. and best of all, you wont need to take those nasty old steroids (prednisone). Anyway, i won't go on anymore now, or you will be adding eye strain to your list of symptoms LOL. good luck with everything, do post back to let us know how you get on and obviously if you get any other odd symptoms that you want to discuss or need help with:) thinking of you:) x